


Something New

by Sedatephobia



Category: Undertale (Video Game), VoidSwap (Undetale AU)
Genre: Alternate Universe - Undertale Fusion, Anal Sex, Angry Sex, Cheating, Dicks, Dubcon or Noncon Moirallegiance, Gaster - Freeform, General Grillby, Grillby's, Grillby's Backstory, M/M, Plot What Plot/Porn Without Plot, Porn, Sex, Tentacles, goo, selfcest
Language: English
Status: Completed
Published: 2016-06-29
Updated: 2016-06-29
Packaged: 2018-07-18 23:37:28
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,856
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/7335607
Author URL: https://archiveofourown.org/users/Sedatephobia/pseuds/Sedatephobia
Summary: <blockquote class="userstuff">
              <p>Grillby's life has been same in same out.<br/>Wake up, work, clean, watch Tv until Sans falls asleep, go home.<br/>It's time something new happens</p>
            </blockquote>





	Something New

**Author's Note:**

> This is my interpretation of Grillby combined with Gasterfile's Voidby from their VoidSwap AU.
> 
> Go check out his blog! It's full of amazing NSFW and SFW art.  
> Mostly Grillster.  
> Which is A-okay in my book.
> 
> So, uh. Who likes selfcest?  
> Leave a comment if you like it, hate it, there's a typo I missed.  
> I've tried three times to HTML links into this thing.   
> I give up.  
> Enjoy the words.

A bartender has many duties. Not only to keep his bar well stocked but to act as an over-the-counter therapist. To listen and offer advice when the time was right, or to just let patrons talk over themselves until the issue, whatever it was, was hashed out. 

Grillby was an unwilling perfectionist as a therapist. With his soft, almost reluctant, voice customers were made to feel as if they could use the flame as a confidant. He made them feel special. Like they were the only one he was giving his attention to. It was one of the reasons Grillby’s was so popular. In reality, the monster couldn’t care less about the problems his customers had. They were mundane. Same problems in an out. Yes, he was cheating on you. Have you ever thought you’re the reason that you can’t keep a date? Communicate with your family/friend/brother. Grillby was old. Ancient. Even he had stopped counting the years. 

He had been through the war between humans. He had been caged, he suffered from crippling addiction. The petty problems of his patrons hardly touched his radar of care. And yet, here he was, listening to monsters day in and day out with the exact same problems. Was this what his life had come to? Even Sans was starting to grate on his nerves. As much as he loved the small monster, life was too simple. 

Wake up, work, clean, watch Tv until Sans falls asleep, go home. Some nights he didn’t even sleep anymore. After leaving the brother’s place he would wander around the streets of Snowden looking for something new. Some nights, he longed to come across a small monster just so he could stop itching, stop the constant ache. But Sans had found out about his little habit and scolded him. “you’re better than this, grilby. i thought we had gotten passed this.” He hasn’t. Sans just liked to ignore the less pleasant aspects about him. Usually, Grillby was alright with that, he knew he wasn’t perfect, but neither was Sans. 

With a long-suffering sigh, the barkeep blinked back to the present and gave a curt nod as one of his more morose patrons finished up explaining what was wrong today. Grillby couldn’t even remember what the story was about, he had zoned out there at the beginning. He knew it wasn’t closing time, but he decided to usher everyone out anyway. The thought of past dust piles and small barely sentient monsters opened up a carving deep within his twisted silver soul. The flame thought it was best to keep get everyone away from him. He had closed up early before, so he knew the patrons didn’t mind overly much or at least as much as Sans would if he accidentally killed one of his friends. As Judge, Grillby didn’t think Sans could really let him slide past. 

Asgore had a very, very strict policy on monster violence. It was not to be tolerated. They could argue and fight and hate each other all they wanted but as soon as someone’s magic was released, there would be consequences. It didn’t matter if they tried to explain. Zero tolerance. For a monster like him, who didn’t have to release their soul magic to cause pain, were under harsher scrutiny. One of the many reasons Grillby refused to go see his King when summoned. Asgore was a hypocrite. He has commanded the war. He had agreed to promote his young friend through the ranks. And as soon as the, then young, Grillby excelled at his given task the King turned his back to the flame.  
With a sharp shake of his head, Grillby forcibly ignored the wandering thoughts and turned back to his task. He shelved the bottles back to their proper places, throwing out the empty cans, cartons, and multicolored bottles. He placed the chairs on their respective tables so he could sweep up the dog hair and mess the guards had made. He didn’t mind the dogs, they were always polite and didn’t unload on him after, what he assumed, was a long day of nothing. In a momentary lapse of self-control, Grillby released a portion of his burning magic. He sighed heavily as he relaxed, letting the summer haze float around him for a moment before letting it rush over the bar. Leftover puddles of alcohol catching fire in the intense heat wave before burning to nothing on the magic’d wood. His bar would never burn, again at least. After the first accident and required rebuild the bartender had found a monster to fireproof the entire structure for him.

Grillby, who has his eyes closed from the feeling of release, didn’t notice one of the small fires continuing to burn long after it’s fuel has been consumed. He did notice, the sudden surge of power as something appeared in his bar. It didn’t teleport like he knew his favorite patron could. It just was. One moment nothing, and in the next, there was this overwhelming power and, nothingness. For a moment his vision was obscured by deep rolling clouds of smoke. Grillby did not like this at all. This was too different, too strange, too unexplained for his struggling strategist's mind.

Deciding his life was worth the slap on the wrist he would most likely receive, Grillby drug out his entire repertoire of immense magic. It hung behind him like large golden wings, a phantom of his true form. The golden magic did little to illuminate the bar, the light seeming to just bounce right off the oily smoke. The flame knew the bar like the back of his hand. Especially now that it was cleaned and neat. If he could just make his way to the door he could get away. His escape plan was brought to a screeching halt as he felt sharp claws scratch at his neck. The veteran froze in place, darting golden eyes around in the darkness, he couldn’t even make out the arm the hand was connected to. 

All of a sudden the suffocating blackness was lifted and Grillby came face to face with a horribly twisted version of himself. It was strange and he would have thought on it longer if the new creature hadn’t brought his other hand up to dig it’s claws into his shoulder, making him hiss with pain. This thing, whatever it was, was not being gentle. It was not letting him go either, causing the orange monster to panic, ripping himself away from the claws hands to back up against the bar. It was a stupid decision but his mind was clouded with old and new fears. He was bored, yes. He wanted something new but this was far from what he had in mind. 

The monster advanced with him, pressing itself up against Grillby’s body, making escape impossible. Desperately, Grillby braced his hands against the other’s chest, trying to push him away, but it was useless. Even though the dark flame was slightly shorter, slightly slimmer than himself it was about as useful as trying to move a wall. It entertained Grillby’s efforts before capturing his hands, raising them above the bartender’s head. It seemed to smirk at him, the horrible mouth that seemed to constantly drip grew into a wider grin. 

Grillby bared his own jagged mouth, hissing in warning at the creature. It didn’t pay him any mind, choosing instead to press their mouths together, cutting off his display. The bartender blinked down at the creature in surprise. Of all things, a kiss was not what he expected. The fear melted away from his mind, making him sag against the bar and against the creature before him. The dark flame hummed in appreciation and with surprising gentleness, unraveled Grillby’s bowtie. The flame made a sound in the back of his throat that he would later deny being capable of producing and moved his hands to fist in the older button down shirt.

The thing pulled back, smirk widening as it saw Grillby’s eagerness, “Are we giving in so easily, then?” Its voice was quiet, barely a whisper and yet he didn’t have to try and listen to it. The sound seemed to permeate his entire being. The monster knew that even if the monstrosity was on the other side of the room he would be able to hear it with the same crystal clarity. “I thought you would put up more of a fight. I’m disappointed.”

If he was honest, Grillby was disappointed in himself as well. He knew this would hurt Sans, if he ever found out, and knew he should have put up more of a resistance but this was exactly what he had been craving without even knowing it. This was new, rough, and altogether wrong. It didn’t matter, though, all the response the bartender could muster was a sharp shake of his head as he focused on undoing the complicated buttons of the old fashioned shirt. He didn’t know what had gotten into him, he was never this forward with Sans. Even though he was the one who did most of the work, per usual, he allowed Sans to call the shots in bed. Although Grillby yearned to hurt the small skeleton, he held back. He knew Sans would enjoy it but he didn’t know if the monster’s meager HP could take it. Grillby knew, if he killed Sans he wouldn’t be able to live with himself. 

“Ah, don’t think you’re in control.” A clawed hand recaptured the wrists that had only managed to undo one button. The creature leaned his face towards his captive partner’s and hummed in thought. It could do very many things to this monster. It knew he would enjoy them. It had been watching Grillby from the Inbetween and knew the monster’s desired better than Grillby did himself. Knew of the unfulfilling relationship, the boring existence, the secret longing for chaos and destruction. The creature thought of itself as a merciful being, or at least it tried. Even before the accident, it had low impulse control. And now? Now it was nonexistent. If the thought crossed its mind it would be spoken or acted upon. It made the monster’s monster unstable and beyond dangerous. 

It hissed in Grillby’s face before devouring his mouth with its own. Grillby, unused to being the one to submit fought back for control, almost unknowingly. He struggled in the relatively lax grasp and succeeded in pulling one of his hands out of the grasp, although earning himself something akin to a cut from the razor sharp claws. The thing pulled back with a snarl, not liking being interrupted, “I told you, you’re not the one in control anymore.” The soft voice had been twisted into a rough growl in sudden flaring anger.

“...Just who are you?” It was the first time Grillby had spoken through the entire ordeal and his usual strong, but quiet, voice was reduced to little more than an inaudible waver. He was thrown way off track. This was too different, too strange and way too new. As someone who was always in command, Grillby didn’t know how to react. His mind was broiling with too many thoughts at once, causing the rather inane question to fall out instead of something much more pertinent. 

The entity laughed and tilted its head, staring at the pinned monster with one smoldering eye, “I’m nothing more than you. Ah. Well, that was a bit of a lie.” The creature thought to think for a moment before continuing his planned explanation to the sudden question, “I’m the representation of the worst possibilities and what you can become.” Grillby’s question stopped the culmination of anger. It seeped from his form instantly while dark amusement took its place.

“...” Anything Grillby was about to say was cut off in a strangled cry as the twisted flame ripped his shirt open sending buttons scattering everywhere. The dark Grillby’s movements were jerky and overly rough with desperate need. The bartender found himself not minding the pain as much as he thought he would when the creature raked its claws down his newly exposed torso, darkness bloomed in their wake. In fact, he found himself arching up into the hands, enjoying the new sensations. 

Sans was much too soft with him, he was coming to realize. As a being of fire, he is unable to feel temperature changes and light brushes often go unnoticed. Not to mention not many monsters touched him. He could control his temperature but he hardly bothered, finding it mildly amusing when others winced. He was a fire, what did they expect? Sans only touched him so that the skeleton could feel the burning pain. Grillby pretended he was alright with this, but he really wasn’t. Their whole dynamic was focused around Sans. He supposedly lived for Sans. That’s not what he wanted.  
Thoughts were cut off as sharp fingers tilted his head back, making the bartender stare at the rafters. “I know what you’re thinking. Stop. You’re only allowed to think about me. You’re mine.” It spoke, again, in a half teasing manner, although Grillby knew it was nothing more than a command. The situation was strange. He understood his mirror’s intentions perfectly. In a way, he guessed, they were his own. 

Nails were again pulled down his bruised chest, making the fire arch towards his twin, mouth open in a silent plea for more. This is what he wanted. To be touched. Grillby knew he wasn’t allowed to, but he desperately wanted to be able to touch the demon before him. It was a physical ache. He tugged on the shirt as the creature released his head, letting him look pleadingly up into the singular eye, “...Please.” 

“Please what, pet? Let me hear what you want.” The teasing lit was back but it was much more sinister, darker. There was another command hidden in the sweet words.

Grillby didn’t even know to respond. What did he want? Now that he had the opportunity, his mind was blank and his words were shy, “...To touch?”

It practically purred seeing what the proud monster had been reduced to, begging for something so simple. It thought for a moment before leaning in towards the orange flame, “No.” It bit down on the orange neck hard, not bothering to curb its intentions for the sake of the other. Grillby could take it, it knew. If he couldn’t? Well, the thing thought to itself, he choose the wrong iteration of himself.

He was once a soldier and therefore was good at following commands, he was used to being told no and to go against his better judgment. Although when he did monsters ended up dying. Although he was used to it, the simple no stung. Even more the bite, which had him crying out loudly. And still, he obeyed. Grillby did not move his hands from their position, clasped onto the old shirt. He did not allow himself to react other than what he could not physically stop. Well, mostly. Grillby could tell his doppelganger liked his sounds. Just as he liked Sans’.

It was as soon as the name ran through his mind that the stranger drug it’s makeshift burning mouth down his neck as it’s other hand moved to a very sensitive region, teasing him through the, tighter than ever, cloth. He shivered and braced his forehead on the shorter creature’s shoulder, arching into the dangerous hand against his conscious’ better advice. It reminded him that this was cheating and Sans would never forgive him but as the being shredded the front of his pants, being far too impatient for buttons and zippers, Grillby found himself not caring overly much. 

Grillby blushed bright blue as he felt the twin expose his lower self, the cool air hitting previously making him shiver slightly. It didn’t really occur to Grillby that it wasn’t the air. The temperature difference wasn’t near enough for him to feel. It was more than likely just the fact that someone who wasn’t Sans was making him react this way. 

The creature who belonged more in the Inbetween than in any waking world ran a clawed finger down it’s partner’s shaft, makeshift grin growing wider as the fire melted in his hands, it had to wrap an arm around his waist to keep him upright. “My, such a reaction from something so small. Never been touched like this, have you?” It chuckled and enclosed Grillby’s exposed penis in a large, hot hand. It was methodical in its ministrations. Scientific, even. It examined the reactions different touches brought forth. Everything was cataloged and filed away in the immense expanse of its mind. When Grillby never answered his question, the void being frowned and gave the member in his hand a warning squeeze, “Answer me, pet.”

All that responded to the command was a sound that could have been negative. Or a moan. The dark flame just rolled his eye and pressed his body against the other’s, rubbing its own length against the pointed curve of the barman’s hip. Grillby’s own erection was forgotten by the other being as its hands were working again at his pants, tearing the threadbare material to mere scraps in an effort to satisfy its own need. Grillby hardly noticed until his pants were around his ankles but his belt was still clasped around his waist. 

A bark of laughter stopped all movement from both fires. They stared at each other for a moment. Grillby was mortified and very perplexed, “...I have a belt?” Why did the creature not just undo his pants? How was he going to get home? Streaking really wasn’t in his plans for that night.

“Oh, your face! Good god, I’ve never seen someone look that confused.” It just laughed again as Grillby turned a darker blue, mumbling something under his breath. The void shook his head and unzipped his own pants, not caring to give Grillby the respect of also being pantsless. He needed this too bad right now. It had been literal ages before it had even seen another monster, not to mention gotten some. “Congratulations, you know what a belt is. They are pointless. You shouldn't wear one next time. Turn around.”

Not giving him a change, the smoldering fire forcibly turned Grillby around, bending him over the bar and knocking a few glasses onto the wooden floor where they shattered. The mess and sound were ignored by both parties as Grillby scrabbled for something to hold onto before his rough partner decided to just go for it. 

Either the creature could read minds or it had perfectly imperfect timing. As soon as the thought crossed Grillby’s mind, the alternate pushed into him without warning. Grillby was a creature born of magic, so he didn’t necessarily have all the openings a human would but to the tar fire, that didn’t quite matter. It, too, was a master of magic, even more so than Grillby. He was more powerful, a higher LV perhaps. All it had to do was enforce it’s will and the bartender’s body accommodated its own. 

The flame arched his back and cried out in surprise, pain, and pleasure. The creature at his back paid him no mind, fully focused on his own pleasure. Grillby lost count at how long they had been going on, the demon rutting against him forcefully enough to continue to cause a twinge of pain with each thrust. But that was alright. The flame admitted to himself that he enjoyed it far more than he should. At least until one of the hands snaked around his neck, claws digging into his fireflesh. This was way new and caused Grillby to panic in surprise, forgetting who he was with for a moment.

Frustrated and slowly losing what little control it had, the creature dug its claws into the warm neck as both a warning for the monster to calm down and to ground itself. It wouldn’t do to tear himself apart right then. This was too good, it didn’t want to be trapped in the Inbetween for another eternity. 

It hissed as it ground itself into its companion, far to gone to keep up its usual snark. Right, then the only thing on its mind was the repetitive, harsh thrusting and the impending climax. Dark Grillby had waited centuries for this feeling, this moment. When it happened it washed its mind in white static, making the tentative control on its magic falter. Dark, dark magic oozed out of the fractured soul to coat the floor of the bar in oily tendrils that curled themselves around the nearest surface, Grillby’s legs being included. The trails of magic snaked up his legs, one going high enough to curl around the neglected member, the cold unadulterated magic making him moan out loudly. A sound that rose in pitch and volume as the void emptied years of pent up frustration coated oily black into the bartender. 

With that, it was gone. The tendril curling around him was gone. The thing itself was nowhere to be seen. The only evidence was a strange feeling in the pit of his non-existent stomach and a few shards of glass. Oh, and his ruined pants.

Grillby sunk down to the floor, starting where the oily magic was seconds before, trying to convince himself that it wasn’t a dream or maybe that it was a dream, he wasn’t quite sure. He wasn’t sure how he was going to get home, either. Or at least to the brothers'. Usually, he had a spare outfit in his kitchens but he had taken it home to wash after an accident that involved Sans and a certain red substance that he no longer allowed in his bar.

Sans was going to come knocking at any moment, most likely worried that the bartender was trapped in his own mind again. Thinking quickly, the fire stripped off the rest of his clothes, re-tied the apron around his waist, wincing as the rough fabric touched the head of his still hard member and climbed up on the bar, waiting for the small skeleton.

But not before burning the remnants of his clothes. Hopefully Sans would be too surprised by his state of undress to question the lack. 

Time passed and Grillby was growing slightly annoyed with his partner, it was close to one AM and he hadn’t heard a thing from Sans, usually the skeleton was almost frantic with worry. Just as the monster was about to write the whole thing off, the small monster popped into existence, “ey, gillbz, you in he- er.. whatcha doin’ there bud? ya drunk or somethin’?”

"...You took too long, Sans. ...I was worried you didn't care," Grillby put on a mock pout, winking at his skeletal partner, before beckoning him over. 

As Sans descended upon him, Grillby swore he heard a whispered world and the disappearance of a thick oily tentacle. “You’re pathetic, trying to keep up appearances. As if you’ll ever be satisfied by him now.”

**Author's Note:**

> Trying one more time.  
> Copy/paste the ugly links!  
> UGH, I give up. :I
> 
> Gasterfile's Blog: http://gasterfile.tumblr.com/  
> Voidby Ref: http://gasterfile.tumblr.com/post/146579848781/shows-up-to-the-undertale-au-party-6-months-late  
> VoidSwap AU: http://gasterfile.tumblr.com/post/146581243076/voidswapgrillby-headcanons


End file.
